Control moment gyroscopes (CMGs) are commonly employed in satellite attitude control systems. Generally, CMGs include an inner gimbal assembly (IGA) supported by a CMG housing or a stator housing. The IGA typically includes a rotor assembly comprised of an inertial element (e.g., a ring or cylinder) coupled to a shaft. The rotor may be coupled to a spin motor, which allows momentum to be stored in the CMG. To permit the rotor to rotate about a spin axis, spin bearings may be disposed at either end of the shaft. To selectively rotate the IGA about a gimbal axis orthogonal to the rotor spin axis, a torque module assembly (TMA) is mounted to a first end portion of the stator housing. In this way, an output torque is produced that is orthogonal to the rotor spin axis and proportional to the gimbal rate. The TMA may further include one or more rotation sensors (e.g., a tachometer, a resolver, etc.) suitable for monitoring the rotational rate, commutation, and/or the angular position of the inner gimbal assembly. A signal module assembly (SMA) may be mounted to a second end portion of the stator housing opposite the TMA. The SMA functions to deliver electrical signals and power across the rotary interface to the electrical components of the IGA assembly (e.g., the spin motor and electronics). Typically, the CMG housing is evacuated to provide a vacuum environment for the IGA.
As the CMG operates, the temperature within the CMG housing may increase. Over time, the temperature within the CMG housing may exceed an acceptable threshold. As a result, temperature-sensitive components, such as the spin bearings and/or the spin motor, may have shortened useful lives. Although fans and other cooling components have been employed in the past to cool temperature-sensitive components, these cooling configurations may be improved. Specifically, the addition of fans and other cooling components to the CMG may add weight, which may hinder improvements to CMG efficiency. Additionally, because the additional cooling components may consume a volume of space within the CMG, other components of the CMG may need to be reconfigured or repositioned within the CMG, which may increase cost and design complexity of the CMG.
Accordingly, it would be desirable to provide an improved CMG having a cooling system for maintaining an interior temperature below a threshold temperature. In particular, it would be desirable for the CMG to have a relatively low overall weight and for the cooling system to occupy a minimal portion of the CMG interior volume. Moreover, it would be desirable for the improved CMG to be relatively simple and inexpensive to manufacture. Furthermore, other desirable features and characteristics of the inventive subject matter will become apparent from the subsequent detailed description of the inventive subject matter and the appended claims, taken in conjunction with the accompanying drawings and this background of the inventive subject matter.